1. Field of the Invention
The present invention generally relates to moving-picture processing apparatuses and methods for pre-fetch control, and particularly relates to a moving-picture processing apparatus provided with a pre-fetch memory and a method for pre-fetch control in such a moving-picture processing apparatus.
2. Description of the Related Art
Patent Document 1 shows a MPEG decoder with a cache memory and an external memory where the MPEG decoder decodes an MPEG stream that is compressed and coded according to the MPEG (Moving Picture Expert Group). The cache memory serves to pre-fetch and store a portion of a decoded picture stored in the external memory.
There is a technology that utilizes image feature parameters in order to improve a hit rate with respect to the cache memory (see Patent Document 1). The method that utilizes image feature parameters for the purpose of improving a hit rate with respect to the pre-fetch memory requires highly sophisticated computation such as predicting a pre-fetch area required for a next step after decoding a moving vector according to the MPEG decoding process.
Accordingly, there is a need for a moving-picture processing apparatus and a pre-fetch control method that can improve a hit rate of a rectangle-read request issued from a predetermined circuit with respect to a cache memory without performing complex computation such as the reconstructing of a moving vector and the predicting of a pre-fetch area, thereby improving the processing speed of the predetermined circuit.    [Patent Document 1] Japanese Patent Application Publication No. 2006-31480    [Patent Document 2] Japanese Patent Application Publication No. 2002-163150